Linear nitrogen-containing polymers



Patented June 27, 1950 UNIT-ED? STATES; PATiEN oE-moa;

- LINEARINITROGEN-CONTAINING' I? I POLYMERS RObeIt Wigh-ton M'oncriefi, Borrowash,-* near Del-bit England, assignor, by mesne assignments, to Celanese-Corporation ofrAmerica;.-a

corporation ofa Delaware No..D1 awing.= Application August 4, 1945, Serial No.609,'031.1 ln Great Britain May 10, 1945 Claims: (o1; 260'-2) structural unit the .4-amino-1,2,4-triazo1e nu- 10,.

cleus. They are not in .general hydrolysable by hydrochloric acid,as is the case with the known .poly'arnides, .and generally they exhibit, very considerable stability} Moreover, someof them, and notablyithe polymer'fromr sebacic 15 dihydra'zide, have. melting points which. render thememinently suitable .fo'r the production of filaments" for usein textile .materials. The polymer fromjsebacic dihydrazide has a melting point ofthe order of- 250 C.;"which is above the usual ironing temperature for textileliabrics, and. yet permits 01'' the polymer'bein'g spun into filaments from the melt.

The'invention includes making the'new poly-.

mers from anydicarboxylid acids which contain 5 two carboxylic acid groups asthe sole substituent radicles in the hydrocarbon chain, for example 1.- succinic acid, glutaric acid, 'adipic' acid, pim'elic. acid, "suberic acid, azelaic acid;isebacic'acid and;

the higher. 'dicarbo xylic acid'soffthis' series, di-' phenic ."acid'; "phenylene" 1,4- .diacetic', acid and similar" dic'arboxyli'c "acidspfithe aromatimseries. Preferably polymethylene dicarboxylic acids. such as those mentioned. above are used; How.-

eventhe invention "does not excludatheuse 'of dicarboxylic acids containing substituents' or hetero atoms whichrdo not interfere with the reaction, for exampleidiglycollic acid, N-methyl-- imino-diacetic acid and similar dicarboxylic acids containing unreactive atoms in the chain. In- 49 stead of using the dicarboxyliciacid dihydrozide, a mixture of a dicarboxylic' acid diester with the appropriate amount of hydrazine may be used. For ziexample, the. methyl ethyl or phenyl esters are? allwery suitabie for-the purpose of the pres ent: tinvention; Indeed r the: dihydrazides 1 canreadilytbe made -from the dieste'rs' and hydrazine" hydrate. The structural unit of the? polymers: appears to have the: general rformula 1 r 50 carboxylic acids-:thisistructura1 unit: reduces to. the form llq'H i v i -l'- oni)w.o\ NN- where n is :th'e" numbe'rl of methylene groups' in" the dicarboxylic acid? As? explainect belowptha hydrogen l atoms of the 4-amino group may= be rep'lacedby organic radiolesflby a suitable 'afte treatment 'or 'by" using suitabie fraw materials al readylsubstitutedz-fi g The: condensation mayy as:indicated, -Tbe* =car-" "ried out by: simple heating; Usually tempera-' tures of' the' ordenof "200 300 cifandaespeciaily i 230-'280 C.," are suitable for'uthe" purposer The heatingamay be -carried out ona the 'und'ilut-ed dihydrazide; or thedihydrazide maybe -suspende'd 20 or dissolved" in a suitable diluenuii It ha's been found that-. th'e presencea'ofwater==is very bene-" ficial, at least in?the ir'iitial sta'gegrof -the con densatio'ngsincef it fappears ?to preventx or retard a tendency for the polymer to become resinous and 1 insoluble? possibly by cross-tirikingaor: some other side reaction. In addition itiihajss'sbeen found that the presence .ofian additional amount of hydrazine over and above that inecessary to form the dihydrazide isdot great benefit in obtaining poiy'mers of the. desired-4-amino-triazo1e structure. It appears probable that the dihyclrazides exhibit some .tendency to lose hy-iv drazine during the condensation, and. that, the... presence .of additional hydrazine .in the reaction, W vessel restrains. this..tendency or compensates. for anysuch loss of hydrazine. It. (is most. advantageous to employ this excess of--ihydrazine, in the form of hydrazine hydrateor an aqueous 7 solution of hydrazine hydrate, sinceth'is pro--v --vides both the hydrazine and the Wate'r..v The...

condensation is "preferably carried out,;at. least g in theinitial stages, inja closed, vessel, ith'ough in the later stages the pressurethat bui1dsf.up., maybe whollyor impart released, and further, 1 towards the end of the", condensation,' the pres-.

sure may be reduced to-"below atmospheric pressure, for example 'down '.to a pressurezof. 10 1'01; evenl5 mms. ofrmercury final reduction 1. of pressurefitobelow atmospheric pressure is not, however, necessary, audit is most convenient to carry ,out the.wholencondensationina closed. vessel with "periodic? or continuous, release.,oi Pressure, for example la release of pressuredown-i to 50 lbs. per square inch.; iIn'i.the case of 'start-,,

ing with a dicarboxylic lacidester and hydrazine,

the excess of..hydrazine,is providedi by startingi with rather-more than 2 molesjof hy'draZineto'L i of dicarboxylicr acid. rwhenflstartingifrom the dihydrazide; theiexcess .orhydrazineis preferably case'of using hydrazides .of .polyinethylene. aegi at.1east..10l%Lotthe.weightrof ithendihtidrazidem to an intrinsic viscosity of at least 0.6, at which stage filaments made from the polymers usually exhibit cold-drawing properties, with consequent increase in their tensile strength measured in grams per denier.

As indicated above, the polymers are extremely stable to hydrolysing agencies and hence there is very little tendency for their viscosity to decrease. Probably they contain terminal hydrazide groups which are capable of further condensation. Such a tendency to further condensation may be eliminated, or in other words the viscosity of the polymer may be stabilised, by hydrolysing these terminal hydrazide groups. For example the polymer maybe heated with an aqueous solution of hydrochloric acid or any other suitable mineral acid to split off the hydrazine at the ends of the chains and thus constitute carboxylic acid groups as the terminal groups. The polymer is then obtained in the form of a hydrochloride or similar salt, and the base may be recovered therefrom by suitable neutralisation of the acid. The polymer then appears to be completely stable as regards its viscosity. -When sufllcient hydrazine has been included in the original condensation mixture to ensure that all the structural units contain the aminotriazole nucleus, the polymer thus produced probably has the structure NH: i xooo R-C/ o- R.COOX

where R is a divalent organic radicle, p is the degree of polymerisation and X is hydrogen or a metal or other salt-forming base. A further possibility of securing a viscosity-stable polymer is to include in the mixture before condensation, or to add to the mixture after condensation, an agent which will combine with or otherwise render ineffective the terminal acid hydrazide groups. Hydrazides of monobasic acids, for example acepoints or decreasing their moisture regain, or even of rendering them completely insoluble in ,organic solvents. Generally the polymers as made are insoluble in water and acetone, and soluble in phenolic solvents, such as phenols, cresols, xylenol and the like, and soluble in for- -mic acid and acetic acid. The polymers may be aftertreated with acylating agents, for example formic acid reacted at water-bath temperature, or acetyl chloride applied at much the same temperature, or phenyl, naphthyl or other isocyanate reacted in boiling benzene or similar solvent, phenyl and other isothiocyanate reacted under similar conditions, or isocyanic acid or isothiocyanic acid. These two latter are preferably applied in the form of alkali salts to the hydrochloride of the polymer. Other acylating agents include cyanamide, which converts the I amino group into a guanidine group, and alkyl,

tyl hydrazide, or longer chain hydrazides, such as lauryl hydrazide, provide-one means of securing this end, though it is probable that some of the acetyl, lauryl or similar monobasic acid residues will appear attached to the amino groups in the triazole rings in the polymer chain. Indeed it is possible to form N-acidylated poly- -aminotriazoles by using part of the hydrazine in the original mixture in the form of a monobasic acid hydrazide. the 2 moles of hydrazine theoretically necessary for the production of a polyaminotriazole may be thus replaced by a monobasic acid hydrazide for each mole of dicarboxylic acid used. Monobasic acid amides, for instance laurylamide and acetamide, may likewise be used for the purpose of viscosity stabilisation.

The polymers may be aftertreated in a number of ways for the purpose of. modifying their properties, for example increasing their melting Up to 1 molecule out of aryl or aralkyl cyanamides. .The polymers so produced probably contain the structural unit It a w where R1 is a divalent organic radicle, X is an or substituted amino group. With the above reagents R2 is monovalent. However it may be a dior polyvalent radicle. By employing an acidylating agent which contains two or more acidylating groups, the polymer may be rendered infusible and insoluble in all organic solvents. Such agents include diand poly-carboxylic acids, diand poly-isocyanates and diand poly-isothiocyanates. In a similar way the polymers may be aftertreated with carbonyl compounds, including both aldehydes and ketones, for example formaldehyde, acetaldchyde, benzaldehyde, acetophenone, i'urfural and the like. Here again reagents may be used which contain two or more reactive groups, for example dialdehydes, diketones, aldehydo-ketones, aldehydocarboxylic acids or ketocarboxylic acids, e. g. levulinic acid.

The polymers treated with carbonyl compounds probably contain the structural unit where R1 is a divalent organic radicle, R2 is hydrogen or a monovalent organic radicle depending on whether an aldehyde or ketone is used, and R3 is a mono-, dior poly-valent organic radicle depending on whether a mono, dior poly-valent carbonyl compound is used. It will be appreciated that both with the acidylating agents and with-the carbonyl compounds, reaction may take place with a small proportion or a large proportion of the amino groups disposed along the polymer chain. The polymers so treated thus contain both modified and unmodified structural units.

'Insolubilising treatments carried out with reagents containing two or more reactive groups are preferably applied to the polymers after into filaments, films or the like.

s a Thezz toflowingi mmplesidllustratei the :invenztion ibutzxare notl-tos bez-consideredvasrlimitingg,it.:::a.

Exemplar A mixtureof 100-i=parts by weight :ofqsebaoic: dihydrazide; 2 parts ruby-weight? of. acetic, hydrazidegaandBO; parts weight I-of water :arerheate in a Staybrite autoclave-M 230? C.'IfO1' "3 hour-spa the; pressure; being-released continuously 'sov -.as to:- maintain; it at 50.:lbs. ,persquare inch 1; At" the =3 end of -the 3 .hou-rs=thesintrinsicwiscosityiof the polymer =1 is ;"2 1,b0l1t=: .0.3O.-35; and I the .-po lymeri:.is 4 already;- ifibrer-forming; Thealow 'p01ym&r%t:thus formed is then heatedior. a further: :ha1f- -an-hour;- at-2303 "C.'-.1under-;a:pressure 'of1101mms.'- The product, then has van: intrinsic viscosity; of -athe order Of%: .0.75,' and readilyuforms :flbreswrhichn cani'bez-coldedrawna, I

100 rpartsebyi weight. of. .jsebacic4.-hydrazide are heated, iwith-. "19.5 parts. by. weight, of. hydrazine: e inthe-for-m-Oran-aqueous solution containing 50% n hydrazine @hydrate: in an; autoclave for shalt an hour. ats-2202 C.,-1on2 hours a at 260F270 C., the i autoclave: being kept closed. throughout these operations andafinal-ly for-.half an: hour ate260-' 2710 10., duringavhich :time th pressure is grad 1 ual1y .-reduced-to-c50 lbsraper square inch... The a polymer-,-. which has ma @melting point' of--.about 250 C., yields long lustrous filaments fromctheam melt which canebe cold-drawn.=-\ Its intrinsic viscosity is about 10.6.

Example-II I 100 parts by weight of sebacic dihydrazide and parts by weight of hydrazine in the, vform of. an aqueous solution containing 90%of hydra?" zine hydrateiareheatedtinmnautoclave for-2 i hoursat' 22'0""C.,an d for'a JfurtherCZ 'hours ati 260 C. The product; whichyieldsiongfilaments" from the melt, hasnan' .intrinsicyiscosity jOf about 52112, melting point oiabout 255 C.;Iand' if; a nitrogencontentzof-28l2%.

Example IV 100 parts :by weight-of sebacic hydrazide and 7.8 parts of hydrazine inthe form of an aqueous solution containing .of hydrazine hydrate are heated in an autoclave for 1 hour at 220 C., the pressure then released to 200 lbs: per square inchg 'the temperatureiirapidly raised :tow2 C.- and maintained? at that figure :for a further" 2 hours whilststabil'ising thepressure at- 200 'l bs't per squar e inch" Icy-aperiodic releasez Thexproduct which= laas ,good fibre-forming :propertiesahass an intrinsic viscosity of 0.75.

Example V parts by weight of suberic dihydrazide are heated with 19.5 parts bye weight'of hydrazine in 605% the form of an' aaqueous -solution containing 50% of hydrazinehydrateinanwautoclavelfor 2 hours at 220 ""C.,' Atth endof this period; the product has a melting pointiof.:253?1C.-,wancintrinsic viscosity of 0.4 and a nitrogen con The'imroduct is then further "h'ated fof r hour at 280 C. under presure of 5 inmsr'of rhercu-rya It is then capablewofwieldingi'longrsfilaments and has a melting point of 292-294f.,C.

The polymer from azelaic; dihydrazidemhasna meltingxpointlof the order of 23 '4STC., thatwfromd; adipic dihydrazideia melting:,pq n't of 280:3C:,'Z andrthati from succinic'dih'ydrazide a meltingzrl. point above 360C? These polymers are'ioimed by methods similar to those given in the above 76 polyamino-triazoles of the presents-invention @acid contentmeglecting:terminal:aminor group "ace goiireducing-ianytendency: to decomposition :durin meat jatmospheric' tem examples arorasebacicn and suloerici dihydrazides Ima similarwvayethe;diestersrof dicarboxylicracids mayzvbeacondensed witm hydrazin'eze Asaalreadyrindicatede:ea mharacteristicnof.flzthe theinar:extraordinarysvimesistance-; -1tor-hydrolysing agencies. In particular; rtheir wiscosity:inemetaaa; cresolrsis isuhstantiallyz,unafiected -b-ymhoiling:tliem with r-zdilute. on:aconcentrated ehydrochl'oric risacidz-ai:

for :th'er ipoiymer-;::would =obe wequivalentn'to one quarter of the nitrogenszcontentc:'that'uisvtoi-sayw. f orb-each 156; gramsazzofsnitrogenu present: :th'ere wouldhetpresent'zfififif gramsrofvhydrochloric facids'i in 1 the:-hydrochlorida);i z Generallylfthe: polymer are watereinsolubleeamhzthazmostiivaluable; one are tho'seainawhich;the;linkscjoiningmthe triazolel ringszar-e suchxithatxthet:total nitrbgerr rcontentu-i; of the polymerr-zis .:more:than :15 95:1;-

The zinventionincludeszthea.--productiori :ofsfllaee ments fllmsandt other:-articles.ironrthexpolyn rersrr produced as idescrlbed-rabovew Ge'nerallythe; most" suitable'amethodrmf producing filaments"" i y irextrudingf a melttoiathe melt l spinninggci e..

35a3polymer-rthroughitsuitablei rorificese lnfi-tgeneralre the temperature? ofethe zpoly'mer-r'tor lia-extruded v should be: s0me* 10"-'30- Babove? th rum-elting-apoint' of thepolymerc r Thiszmeltin'g temperatureima be modifled to some extentyexg. withzia viewrto' spinning atwerythigh temperatures; by mixing, the polymer with suitable proportions :sof "plasti-z cisers; forr' exa'mplel isulphon'amide 1 plasticisers;

phenolicE'plasticisersy \ureapand thiourea": plasttiw- -,ig cisers andathe like: Such plasticisers:may1either be? left in the rproducts -or; may :be? partially! or r completely extr-acted' therefrom? Filaments mayaii also =be producedsby'r wet or *dry splnnin'g methods: fromsolutions in suitable-i solvents, for "example boaeiormic acid or acetic acid or the phenolic solvents '11::

referred =to"ab'ove Th'' filaments so: a formed may, if tlre-polymer=-r-' be of sufliciently high molecular weight, be drawna: 1- out at comparatively lOW'temperatures; "or even" perature, to veryfine filaments havmg higWtenacity"and good elasticity; Th resultingfilaments'may'thn -b used for 'any: of i the purposes towhichartificial sillfs have-inf-the past beerr appliede Gnerallyi'the products have an affinity f or "the dispersed insoluble type -of 'dy' stuff-ii'iow'generalliapplied-to'-cellulose acetat while -those'in which the '4-amino groupfi-has nov been modifld 'or in which only i a proportion of such 'amino *groups has undergonemodification While the invention is especially dircted tow the manufacture andapplication of flbr'e' foiming polymers, it is' not i-irnitedthe'reto and embra'c theproduction offlsirn'ilali' polymers"suitablef-ioraceto-butyrate, butyrate and aceto stearate, ethyl cellulose, oxyethyl cel1ulose,' oxyethyl cellulose acetate, benzyl cellulose and other cellulose derivatives, plasticizers or softening agents, dyestuffs, Pigments andthelike. i

Having described my invention, what I desire to secure by Letters Patent is:

1; Process for the production of nitrogen-containing polymers, which comprises heating a dihydrazide of a dicarboxylic acid free from reactive groups other than the carboxy groups with suflicient hydrazine to produce a polymer resist-- ant to hydrolysis by hydrochloric acid, and continuing the heating until the polymer is produced.

2. Process for the production of nitrogen-containing polymers, which comprises heating a diester 'of a dicarboxylicxacid free from reactive groups other than the carboxy groups with more than two molecular proportions of hydrazine to produce a polymer resistant to hydrolysis by hydrochloric acid and continuing the heating until the polymer is produced.

3. Process for the production of nitrogen-containing polymers, which comprises. heating at'a temperature sufiicient toj'liberate free hydrazine from a monocarboxylic acid-hydrazide a dihydrazide of a dicarboxylic acid free .from reactive groups other than the carbox-ygroups with a sufiicient quantity of 'a hydrazide of. a monocarboxylic acid free from reactive groups other than the carboxy group'to produce a polymer resistant to hydrolysisbyhydrochloric-acid, and continuing' the heating untilzthe polym'er is produced- 4. Process for the production of. nitrogen-containing polymers: 'which:icomprises heating ,a

dihydrazide of a dicarboxylic acid free from reactive groups other than the carboxy groups with suflicient' hydrazine to produce a polymer resistant'to hydrolysis by hydrochloric acid, and continuing the heating until the polymer is produced, at least the initial heating being carried out in the presence of water.

5. Process for theproduction of nitrogen-containing polymers, which comprises heating-a dihydrazide of a polymethylene dicarboxylic acid free from reactive groups other than the carboxy groups with sufficient hydrazine to produce a polymer resistant tohydrolysis by hydrochloric acid, and continuing the heating until the polymerisproduced. w t 3 6. Process for the production of nitrogen-containing polymers, which comprises heating a diester of a polymethylenedicarboxylic acid free from reactive groups other than the carboxy groups with -more than two molecular proportions-of hydrazine to produce a polymer-resistant l to'hydrolysis byhydrochloric-acid, and continuingthe heating until the polymer is produced.

'7. Process for the production of nitrogen-comtaining polymers, which comprises heating a dihydrazide of a dicarboxylic acidfree from reactive groups-other thanthe carboxy groups with sufilcient hydrazine to produce a polymer resistant to hydrolysis by hydrochloric acid, and continuing the heating until the polymer has fibre-- forming properties.

8. Process for the production of nitrogen-containing polymers which comprises heating a diester of a dicarboxylic acid free from reactive groupsother than the carboxy groups with more than .two molecular proportions .of hydrazine to.

produce a polymer resistant to hydrolysis by hydrochloric acid, .and continuing the heating until the polymer. has fibre-forming properties.

0 Number Name Date 2,218,077 Zerweck et al. Oct. 15, 1940 2,332,303 DAlelio Oct. 19, 1943 2,349,979 Moldenhauer et a1. May 30, 1944' 2,395,642

9. Process for'the production of nitrogen-con taining polymers, which comprises heating a dihydrazide of a polymethylene dicarboxylic acid free from reactive groups other than the carboxy groups with sufficient hydrazine to produce a polymer resistant to hydrolysis by hydrochloric acid, and continuing the heating until the polymer has fibre-forming properties.

10. Process for the production of nitrogen-containing polymers, which comprises heating sebacic dihydrazide with sufiicient hydrazine to produce a polymer resistant to hydrolysis by until the polymer is produced. 1 I

hydrochloric acid, and continuing the heating 11. Process for the production of nitrogen-con taining polymers, whichcomprises heating sebacic dihydrazide with water and sufficient hydrazine to produce a polymer resistant to hydrolysis by hydrochloricand, and continuing the heating until the polymer is produced.

12. Process for'the production of nitrogen-containing polymers; which comprises heating s'ebacic dihydrazide with sufiicient hydrazine to produce a polymer'resistant to hydrolysis by hydrochloric acid,"and continuing the heating until the polymer has fibre-forming properties.

13. Linear nitrogen-containing polymers characterized by being substantially resistant to the hydrolyzing action of boiling hydrochloric acid,

and consisting of structuralunits of the general formula 1, 7. R C\\/H\C.

and consisting of structural units of the general formula l I r m on,). o c- .ROBERT MONCRIEF'F.

REFERENCES CITED UNITED STATES PATENTS Prichard Feb. 26, 1946 

1. PROCESS FOR THE PRODUCTION OF NITROGEN-CONTAINING POLYMERS, WHICH COMPRISES HEATING A DIHYDRAZIDE OF A DICARBOZYLIC ACID FREE FROM REACTIVE GROUPS OTHER THAN THE CARBOXY GROUPS WITH SUFFICIENT HYDRAZINE TO PRODUCE A PLYMER RESISTANT TO HYDROLYSIS BY HYROCHLORIC ACID, AND CONTINUING THE HEATING UNTIL THE POLYMER IS PRODUCED. 